Since the beginning of antiquity, both pharmacy and medicine have long sought a delivery system for the controlled, programmed administration of a beneficial drug composition to a biological environment of use. The first recorded mention of a delivery system, a drug form, is in the Eber Papyrus written about 1552 B.C. The Eber Papyrus mentions dosage forms such as anal suppositories, vaginal pessaries, ointments, oral pill formulations, and other dosage preparations. About 2500 years passed without any advance in dosage form development, until the Arab physician Rhazes, 826-925 A.D., invented the coated pill for oral use. A century later the Persian Avicenna, 980-1037 A.D., coated pills with gold or silver for increasing patient acceptance and for enhancing the effectiveness of the drug. Also around this time the first tablet was described in an Arabian manuscripts written by Al-Zahrawi, 936-1009 A.D. The manuscript described a tablet formed from the hollow impression in two matched-facing tablet molds. Pharmacy and medicine waited about 800 years for the next innovation in dosage forms, when in 1883 Mothes invented the capsule for administering drug. Fifty-five years later Lipowski introduced a convenience dosage form to pharmacy and medicine by eliminating the necessity for taking an oral dosage form several times during the day. The dosage form invented by Lipowski in 1938 comprised a number of small beads containing a dose of drug with several thicknesses of coating designed for the slow and constant supply of drug. Eighteen years passed before Blythe introduced a tiny-timed pill dosage form similar to Lipowski's. This introduction established in pharmacy and medicine a permanent position for prolonged action, timed release dosage forms.
The next quantum and profound leap in dosage forms came in 1972 with the invention of the osmotic device by inventors Theeuwes and Higuchi. This unique delivery device is manufactured in one embodiment for oral use. In this embodiment it embraces the appearance of a tablet with a drug delivery osmotic passageway. It is the first oral dosage form that delivers throughout the entire gastrointestinal tract a known amount of drug per unit time of a dosage-controlled rate of delivery. A further pioneer advancement was presented six years later to the dispensing art by inventor Theeuwes. In this advancement, the delivery kinetics of the device was enhanced for delivering drugs with degrees of solubility in aqueous fluids that are difficult to deliver, such as very soluble or insoluble in the fluid, by manufacturing the device with an agent compartment and an osmagent compartment separated by a film, which film is movable from a rested to an expanded state. The device delivers agent by fluid being imbibed through the wall into the osmagent compartment producing a solution that causes the compartment to increase in volume and act as a driving force that is applied against the film. This force urges the film to expand against the agent compartment and correspondingly diminish the volume of this compartment, whereby agent is dispensed through the osmotic passgeway from the device. A more recent advancement in oral dosage forms was provided by Cortese and Theeuwes, who use a layer of a hydrogel for urging a layer of a beneficial drug from an osmotically operated delivery device. The device delivered the layer of drug by the hydrogel expanding and urging the beneficial drug through an osmotically calibrated passageway from the device.
While these prior art devices operate successfully for their intended use, and while they can deliver numerous difficult to deliver drugs, their use can be limited because of their structure or because of the manufacturing steps needed for fabricating a movable film or for fabricating a layer arrangement in the device. It will be appreciated by those versed in the dispensing art, that if a dispensing device can be provided without the movable film or the layer arrangement, and can be manufactured free of the tribulations known to the prior art, such a device would have a positive and practical value and represent also an advancement in the delivery art.